The present invention relates generally to vehicle seat assembly and, more particularly, to a seat latch system operable to adjustably recline the seat back, selectively lock the seat back in an upright position and a folded position, and place the vehicle seat in stowed and deployed positions, with an interlock mechanism interconnecting a seat-back latch mechanism and floor-latch mechanism to ensure a predetermined sequence of latch operation.
Seat assemblies of the type used in motor vehicles are commonly equipped with locking pivot mechanisms that can be selectively actuated to permit angular adjusting of the seat back relative to the seat bottom, thereby providing added comfort and convenience to the seat occupant. Typically, these locking mechanisms include a housing fixed to the seat bottom, a quadrant fixed to the seat back and supported from the housing for pivotal movement about a first pivot point, a lock pawl supported from the housing for pivotal movement about a second pivot point, and a release actuator for causing movement of the lock pawl between first and second positions. In its first position, teeth in the lock pawl engage teeth on the quadrant for preventing movement of the quadrant about the first pivot point, thereby releasably locking the seat back in a desired position. In contrast, movement of the lock pawl to its second position causes the teeth to disengage the teeth in the quadrant and permit angular movement of the seat back to a desired position. Typically, the release actuator includes a spring-biased cam for normally locating the locking pawl in its first position. In many seating applications, this type of locking mechanism is used as a seat recliner to permit selective adjustment of the seat back between an upright position and a fully reclined position.
Recently, however, with the increased popularity of pick-up trucks, mini-vans, and sport utility vehicles, there has been an interest in developing seat assemblies in which the seat back is capable of folding forward to a dumped position for providing improved accessibility to storage space or for providing increased cargo area. In pick-up trucks, the ability to fold the front seat backs completely forward permits access to the rearward cab compartment. In mini-vans and sport utility vehicles, the ability to fold the rear seat backs completely forward enables the cargo space to be increased or ingress to be simplified. In known designs, the seat assembly is equipped with a seat-back dump mechanism that typically employs some variation of a pawl-type blocking pivot mechanism. Although pawl-type pivot mechanisms enable a seat back to be reclined to a substantially flat position, they may not enable the seat back to be folded completely forward to improve accessibility to storage space or provide an increased cargo area. Furthermore, vehicle seats must be capable of withstanding extreme forward and rearward forces that result from belt loading caused during a collision. In pawl-type pivot mechanisms, these forces are transmitted to the pawl and the quadrant. As such, the cam must be designed to withstand these extreme forces, thereby increasing the complexity and cost of the seat-back dump mechanism.
Consistent with this focus, there is an interest in developing seat assemblies that are moveable between stowed and deployed positions to improve accessibility to storage space and rearward seating areas or to provide increased cargo area. The stowable seats oftentimes include a latch mechanism that is operable to releasably connect a portion of the seat to the vehicle floor, thereby allowing the seat to be tilted between its deployed and the stowed positions. While existing mechanisms are generally effective at performing this intended function, they may present safety problems. It is essential to ensure that a vehicle seat occupant is not confused as to whether the floor latch is fully engaged before occupying the vehicle seat. Prior designs do not block motion of the seat to a stowed position while the seat back is in an upright or use position, as well as block motion of the seat from the dump position to the upright or use position until the floor latch is fully engaged. That is, such prior designs do not ensure that the seat is not able to pivot when the seat back is locked and that the seat back is not able to pivot when the floor latch is not fully engaged.
Current seat designs sometimes include latch mechanisms that require that the occupant manipulate the respective latches in a specific sequence to ensure proper positioning of the seat in its deployed and stowed positions. Toward this end, seats have included interlock devices for ensuring proper sequencing. While existing interlock mechanisms are generally effective at performing this function, they do not provide necessary safety features, or a consistency of operation, in a cost-effective and simplified interlock arrangement.
A seat assembly according to the invention includes a cost-effective and simple interlock arrangement for ensuring proper sequencing of seat latch operation, whereby a safe seat design is provided. The seat assembly generally includes a seat bottom pivotally mounted to a base at a front portion and releasably mounted to the base at a rear portion, as well as a seat back angularly adjustable relative to the seat bottom. A seat-back latch mechanism interconnects the seat back and the se at bottom for pivotal movement between a use position and a folded position. A floor-latch mechanism releasably mounts the seat bottom to the base for pivotal movement between a deployed position and a stowed position. An interlock mechanism interacts with the floor-latch mechanism and the seat-back latch mechanism to ensuring proper sequencing of latch operation. The interlock mechanism includes a lock-out lever to selectively block operation of the floor-latch mechanism and the seat-back latch mechanism. The lock-out lever includes a segment blocking the floor lock latch mechanism when the seat back is in the upright position and a segment blocking the seat-back latch mechanism when said seat bottom is in the stowed position.